This invention relates to child resistant closure assemblies comprising a co-operating container and cap in which anti-rotation means must be overcome to enable the cap to be rotated to a predetermined angular orientation on the neck of the container (this position being referred to herein as `the aligned position`) at which one side of the cap (referred to herein as the `front of the cap`) can be pushed off the neck in order to open the container.
In such closure assemblies the cap comprises a top wall and a depending skirt, and a co-operating circumferential bead and a lug are provided which engage to prevent the container from being opened, except at the aligned position. At the aligned position the lug, which is on the inside of the skirt at the front of the cap or on the neck of the bottle, can pass through a gap in the circumferential bead which is located on the neck of the container or inside the skirt at the front of the cap, so enabling the front of the cap to be pushed off the neck of the container in order to open the container.
Closure assemblies as described above are referred to herein as closure assemblies of the kind described.
In closure assemblies of the kind described, further engageable means are typically provided on the opposite side of the cap (`the rear of the cap`) which disengage from the container neck on opening, so enabling the cap to be completely removed from the container. However, said further engageable means could be replaced, for example, with hinge means which attach the cap permanently to the container.
The present invention relates particularly, but not exclusively, to a closure assembly of the kind described which is the subject of a European patent application, having the same inventor as the present application, and published as EP 0500265. In this closure assembly, the further engageable means are provided on the rear of the cap and which disengage from the container neck on opening, to enable the cap to be completely removed from the container, and the skirt of the cap is connected by a number of breakable webs to a circumferentially extending tear-off band which in its turn is joined by further breakable webs to a continuous circumferentially extending captive band on the neck of the container. Lugs on the captive band and on the neck of the container engage to provide the anti-rotation means of the closure assembly. In this closure assembly the anti-rotation means prevent the cap from being rotated to the aligned position until the captive band has been disconnected from the cap by removal of the tear-off band, and removal of the band is tamper-evident.
Provision of the anti-rotation means in closure assemblies of the kind described is an additional child-resistant safety feature to that of arranging for the cap to be removable only in the aligned position.
However, these child-resistant safety features may be compromised in random instances of capping in the factory, if it is possible for the cap to be put onto the container already in the aligned condition, since it could then be possible for a child to remove the cap without difficulty. Moreover, where there is a tear-off band, it may be possible to replace the cap without damaging the tear-off band, thereby overcoming the tamper-evidence normally provided by such a band.
In the closure assembly which is disclosed in the previously-referenced European patent application, published as EP 0500265, there is still some significant child-resistance in instances of capping in the aligned position, since, until the tear-off band has been removed, the tear-off band and the captive band make the cap less flexible, and add to the depth of the skirt, so making it difficult to push up the front of the cap to open the container.
Nevertheless, development work has been undertaken to increase the child resistance of the closure assembly should capping occur in the aligned position, and to promote tamper-evidence in such a situation. The present invention arises from this development work.
According to the present invention, a child-resistant closure assembly of the kind described is provided with separable means attached to the cap of the assembly by way of a frangible connection, the assembly comprising detent means on the separable means and on the neck of the container of the assembly, surfaces of the detent means being engageable in the cap aligned position to resist the cap being pushed off the neck of the container until the frangible connection has been broken, said surfaces being engageable in the cap aligned position.
Preferably breaking of the frangible connection is arranged to be tamper-evident. It may, for example, involve the removal of a tear-off band, the absence of which would be clearly visible.
Said separable means may itself comprise such a tear-off band, but most preferably comprises a band such as a captive band which is spaced from the cap by a tear-off band.
The detent means on the separable means preferably comprises a surface of the separable means.
The detent means on the neck of the container conveniently comprises a projection. Most preferably a surface of the projection is obliquely angled relative to the direction of capping of the container, in order to facilitate passage of the separable means over the projection without damaging the frangible connection of the separable means. In a preferred embodiment of the invention the detent means on the neck of the container comprises a projection in the form of a rib, extending partially around the container neck. The rib preferably extends around the neck through less than a quarter of the neck circumference. The detent means on the neck may comprise a plurality of projections disposed around the neck. Where the neck of the container is injection molded, the detent means on the neck is preferably provided on a circumferential bead on the neck.
Where the cap is provided with a tear-off band, the detent means on the neck of the container is desirably located in a gap between the ends of the tear-off band when capping has occurred in the aligned position. Where the detent means on the neck is disposed underneath a portion of a tear-off band, the tear-off band is preferably arranged to deform over the detent means without damaging its connection or connections to other parts of the closure assembly.